Model Maker is used to construct transcript models using combinations of putative exons derived from ab initio predictions or from the alignment of GenBank transcripts, including ESTs and RefSeqs, to the NCBI human genome assembly. The Evidence Viewer summarizes the sequence evidence supporting a gene annotation by displaying alignments of RefSeq and GenBank transcripts, along with ESTs, to genomic contigs. The tool also shows detailed alignments for each exon, and highlights mismatches between the transcript and genomic sequences.